Online Course Discussion Forum

Problem 8.9 help on MC II-B Comb

 
 
Picture of Cory Li
Problem 8.9 help on MC II-B Comb
by Cory Li - Wednesday, 27 May 2020, 9:30 PM
 

Could you confirm that the answer for (a) is (6C3)*(5C1)*(4C1)/(15C5) instead of (6C3)*(5C1)*(4C1)/(15C4) in the book? Thanks,

 
Picture of Areteem Professor
Re: Problem 8.9 help on MC II-B Comb
by Areteem Professor - Monday, 1 June 2020, 10:57 AM
 

The question was supposed to say "$2$ red, $1$ green, and $1$ yellow", since we are picking $4$ balls total. Thus the answer would be $$\dfrac{\binom{6}{2} \binom{5}{1}\binom{4}{1}}{\binom{15}{4}}.$$